.338 Imperial Magnum History /RE-loading /dimensions

[RUMMBLES]

Hello folks,
I’ve been a long time searching for information and every couple years have checked things out. Here I am internet sleuthing again. My father bought a .338 Imperial Magnum along with dies and brass from Aubrey White in the early 1990’s through a shop here in Calgary, Alberta. A year later he also purchased some .338 Canadian brass(Aubrey’s second attempt with brass). Dad’s rifle is serial number IM300003. One of the original 13 production rifles made with Sako. We have been hand loading and hunting with this for elk and moose and love it. I have always been on the look out for more info and a way to make some brass. The Imperial brass as you know is not the best. The Canadian brass has been top notch but I want to ensure the long life of the rifle. I am interested in any information on resizing .338 Edge, .300 Remington Ultra Mag and .375 Remington Ultra Mag brass. The Edge is extremely close to the Imperial. 300 RUM I worry will thin the neck wall too much and 375 RUM may have chamber issues. But from my research the 375 RUM just needs an anneal, run through the full size die a couple times, trim to length, load and shot. I’d like to know if the Edge is even easier. I have the options to buy either brass but may just buy both and try things out. Thanks in advance for any information. Cheers

 

[Flewis]

Hello folks,
I’ve been a long time searching for information and every couple years have checked things out. Here I am internet sleuthing again. My father bought a .338 Imperial Magnum along with dies and brass from Aubrey White in the early 1990’s through a shop here in Calgary, Alberta. A year later he also purchased some .338 Canadian brass(Aubrey’s second attempt with brass). Dad’s rifle is serial number IM300003. One of the original 13 production rifles made with Sako. We have been hand loading and hunting with this for elk and moose and love it. I have always been on the look out for more info and a way to make some brass. The Imperial brass as you know is not the best. The Canadian brass has been top notch but I want to ensure the long life of the rifle. I am interested in any information on resizing .338 Edge, .300 Remington Ultra Mag and .375 Remington Ultra Mag brass. The Edge is extremely close to the Imperial. 300 RUM I worry will thin the neck wall too much and 375 RUM may have chamber issues. But from my research the 375 RUM just needs an anneal, run through the full size die a couple times, trim to length, load and shot. I’d like to know if the Edge is even easier. I have the options to buy either brass but may just buy both and try things out. Thanks in advance for any information. Cheers

I didn’t think the ims had rebated rims like the ums but I read about in the early 90s. The 404 case has been used by a few small gun companies since before ww2.